Glossary of terms

1s – 7s
When referring to ore and stockpiles indicates the amount of extractable uranium in the ore (grade). At Ranger, 1s indicates the lowest grade (waste) and 7s indicates the highest grade ore.
airborne gamma survey
Aerial measurements of the terrestrial gamma radiation using a large volume sodium iodide (NaI) detector on board an aircraft.
alpha radiation (α)
A positively charged helium (He2+) nucleus (two protons + two neutrons) that is spontaneously emitted by an energetically unstable heavy atomic nucleus (such as 226Ra or 238U).
application
A document stating how the mining operator proposes to change the conditions set out in the mining Authorisation. These changes need to be approved by all MTC stakeholders.
authorisation
For mining activities authorisation is required under the Northern Territory Mining Management Act (MMA)  for activities that will result in substantial disturbance of the ground. It details the authorised operations of a mine, based on the submitted mining management plan and any other conditions that the Northern Territory Minister considers appropriate.
becquerel (Bq)
SI unit for the activity of a radioactive substance in decays per second [s-1].
beta radiation (β)
A high energy electron or positron emitted when an unstable atomic nucleus (such as 90Sr or 40K) loses its excess energy.
bioaccumulation
Occurs when the rate of uptake by biota of a chemical substance, such as metals, radionuclides or pesticides is greater than the rate of loss. These substances may be taken up directly, or indirectly, through consumption of food containing the chemicals.
bioavailable
The proportion of the total present (in water, sediment, soil or food) of metals and radionuclides, that can be taken up by biota (see also bioaccumulation).
biodiversity (biological diversity)
The variety of life forms, including plants, animals and micro-organisms, the genes they contain and the ecosystems and ecological processes of which they are a part.
biological assessment
Use and measurement of the biota to monitor and assess the ecological health of an ecosystem.
biological community
An assemblage of organisms characterised by a distinctive combination of species occupying a common environment and interacting with one another.
bund
Embankment or wall designed to retain contents (usually liquids) in the event of leakage or spillage from a storage facility.
Composite sample
Weekly grab samples are collected at Magela creek, with every second sample analysed individually for 226Radium. The alternate week samples not analysed individually are pooled at the end of the season and are referred to as the composite sample. This composite sample is analysed for 226Radium.
concentration factor
The metal or radionuclide activity concentration measured in biota divided by the respective concentration measured in the underlying soil (for terrestrial biota) or water (for aquatic biota).
damp-proof course
A waterproof barrier comprising bitumen and aluminium.
direct seeding
Vegetation is established by broadcasting seed across the area to be revegetated.
dissolved organic carbon
Natural organic material from plants and animals that has broken down and is able to pass through a very fine (0.45 micrometre) filter.
dose coefficient
The committed tissue equivalent dose or committed effective dose Sievert [Sv] per unit intake Becquerel [Bq] of a radionuclide. See definition of Sievert and Becquerel.
dose constraint
The International Commission on Radiation Protection (ICRP) defines dose constraint as 'a prospective restriction on anticipated dose, primarily intended to be used to discard undesirable options in an optimization calculation' for assessing site remediation options.
early detection
Measurable early warning biological, physical or chemical response in relation to a particular stress, prior to significant adverse affects occurring on the system of interest.
first flush
'First flush effects' refers to rapid changes in water quality that occur after early season rains or to the quality of the first flows in a stream. Soil and vegetation particles wash into the streams, sediments on the bed of the creek are stirred up and dissolved substances from soil and shallow groundwater can be flushed into the streams. During this time the electrical conductivity, turbidity and concentration of metals and dissolved ions are higher than usual, pH is often lower. The same type of effects can also follow intense storm events throughout the season.
flume
A channel control structure with known cross-sectional area used to measure flow rate of runoff water.
fulvic acid
A component of dissolved organic carbon that is especially reactive and forms strong complexes with metals. Fulvic acids account for a large part of the dissolved organic matter in natural water.
gamma radiation (γ)
High energy electromagnetic radiation emitted by excited nuclei (for example after an alpha or beta decay) in their transition to lower-lying nuclear levels.
grab sampling
Collection of a discrete water sample for chemical analysis
Gray (Gy)
Name for absorbed dose 1 Gray = 1 Joule∙kg-1. The absorbed dose gives a measure for the energy imparted by ionising radiation to the mass of the matter contained in a given volume element.
guideline
'Guidelines' are set to assist in the interpretation and management of water quality. Guidelines are based on the range of values that occur naturally at the upstream reference site and so are expected to be exceeded occasionally at the downstream site. Guidelines are updated occasionally by the Supervising Scientist to reflect changes in the range of values measured at the upstream reference site.
half-life
Time required to reduce by one-half the concentration (or activity in the case of a radionuclide) of a material in a medium (eg soil or water) or organism (eg fish tissue) by transport, degradation or transformation.
Hydstra
Hydrology data management software package.
IC50
The concentration of a compound that causes a 50% inhibition in a particular response (eg growth, reproduction) of an organism relative to that of a control organism (ie an organism not exposed to the compound).
ionising radiation
Sub-atomic particles (α, β) or electromagnetic (γ, x-rays) radiation that have enough energy to knock out an electron from the electron shell of molecules or atoms, thereby ionising them.
land application
A method for management of excess accumulated water by spray irrigation. The method depends on the evaporation from spray droplets, and from vegetation and ground surfaces once its reaches them.
laterite
In the Ranger mine context, laterite is a local term used to describe well weathered rock and soil profile material that consists primarily of a mixture of sand and silt/clay size particles. It may or may not exhibit characteristics of a fully-developed laterite profile.
limit – general
A 'limit' is the value that an indicator must not exceed as a result of mining operations. Limits apply to uranium and radium. Exceedence of a limit, due to mining related activities, would normally be regarded as a breach of statutory regulations.

The limit for uranium is based on toxicity to local species in accordance with the ANZECC/ARMCANZ Water Quality Guidelines to protect 99% of the species present. The uranium limit was updated in 2004 in light of additional toxicity data.

For 226Ra, the limit is set in accordance with International Commission on Radiological Protection recommendations.
Limit for total 226Ra activity concentration
Definition of the limit of 10 mBq.L-1 for an increase above natural background in total 226Ra concentration in surface waters downstream of the mine was established following recommendations of the International Commission on Radiological Protection. Additional safety factors are incorporated. The limit is based on a dose constraint of 0.3 mSv per year above natural background from the ingestion of 226Ra in freshwater mussels (Velesunio angasi), a 10 year old child consuming 2 kg of mussels annually and a concentration factor of 19 m3.kg-1 for 226Ra from the water column (Sauerland et al 2005).
LC50
The concentration of a compound that causes the death of 50% of a group of organisms relative to that of a control group of organisms (ie a group of organisms not exposed to the compound).
MOL
Maximum Operating Level. The maximum level at which a liquid containing impoundment can be operated.
MCUGT
Current acronym for the upstream station u/s (formerly described as MCUS).
ore
A type of rock that bears minerals, or metal, which can be extracted.
permeate
The higher purity stream produced by passage of water through a reverse osmosis (RO) treatment process.
polished
Water that has been passed through a wetland filter.
pond water
Water derived from seepage and surface water runoff from mineralised rock stockpiles as well as runoff from the processing areas that are not part of the process water circuit.
potable water
Water suitable for human consumption.
process water
Water that has passed through the uranium extraction circuit, and all water that has come into contact with the circuit. It has a relatively high dissolved salt load constituting the most impacted water class on site.
radiologically anomalous area
Area that displays significantly above background levels of radioactivity.
radionuclide
An atom with an unstable nucleus that loses its excess energy via radioactive decay. There are natural and artificial radionuclides. Natural radionuclides are those in the uranium (238U), actinium (235U) and thorium (232Th) decay series for example, which are characteristic of the naturally occurring radioactive material in uranium orebodies.
radium
A radioactive chemical element that is found in trace amounts in uranium ores.
radon
Colourless, odourless, tasteless, naturally-occurring radioactive noble gas formed from the decay of radium.
Sievert (Sv)
Name for equivalent dose and effective dose 1 Sievert = 1 Joule∙kg-1. In contrast to the Gray, the Sievert takes into account both the type of radiation and the radiological sensitivities of the organs irradiated, by introducing dimensionless radiation and tissue weighting factors, respectively.
sonde
A water quality instrument that is immersed in water for measuring (typically) electrical conductivity, pH, turbidity and dissolved oxygen.
speciation (of an element)
The forms in which an element exists within a particular sample or matrix.
stable lead isotopes
Lead has four stable isotopes, three of which, 206Pb, 207Pb and 208Pb, are end members of the natural uranium, actinium and thorium decay series, respectively. 204Pb is primordial only.
tailings
A slurry of ground rock and process effluents left over once the target product, in this case uranium, has been extracted from mineralised ore.
thoriferous
Containing thorium.
toxicity monitoring
The means by which the toxicity of a chemical or other test material is determined in the field over time. The monitoring comprises field toxicity tests which are used to measure the degree of response produced by exposure to a specific level of stimulus (or concentration of chemical).
tube stock
Seeds are germinated in a plant nursery and the young seedlings are then planted out.
uraniferous
Containing uranium.
uranium oxide
An oxide of uranium which occurs naturally or is produced by a uranium extraction process. This is the product from the Ranger mine.
water treatment plant (WTP)
The process system that removes undesirable chemicals, materials, and biological contaminants from water thereby decreasing its ability to harm the environment.
wet season median difference
The median of all data collected over the whole of the season is calculated for both the upstream site and for the downstream site. The median of the upstream data is then subtracted from the median of the downstream data. This difference value is called the 'wet season median difference'.